astroengine writes: "The family of planets circling a relatively close dwarf star has grown to six, including a potential rocky world at least seven times more massive than Earth that is properly located for liquid water to exist on its surface, a condition believed to be necessary for life. Scientists added three new planets to three discovered in 2008 orbiting an orange star called HD 40307, which is roughly three-quarters as massive as the sun and located about 42 light-years away in the constellation Pictor. Of particular interest is the outermost planet, which is believed to fly around its parent star over 320 days, a distance that places it within HD 40307's so-called "habitable zone.""